Effects of vitamin D supplementation on glucose metabolism, lipid concentrations, inflammation, and oxidative stress in gestational diabetes: a double-blind randomized controlled clinical trial

Comparison of Serum Vitamin D Levels in Obese Subjects with and without Type 2 Diabetes Mellitus

Background

Although observational studies have reported a correlation between vitamin D deficiency and type 2 diabetes mellitus (T2DM), epidemiological evidence on the risk of obese subjects suffering T2DM due to a vitamin D deficiency is limited. Therefore, we investigated the correlation between T2DM and serum vitamin D, lipids, blood pressure, insulin indexes in an obese population.

Methods

A total of 1440 participants including 450 healthy controls and 990 obese subjects, 470 without T2DM and 520 with T2DM. Serum vitamin D levels were measured, and the association between low levels and T2DM in obese subjects was examined using multinomial and linear regression analyses.

Results

Of the participants, 35% had deficient or insufficient vitamin D levels (ie, <20 ng/mL). Compared with healthy controls, obese subjects, particularly those with T2DM had lower vitamin D levels. Multinomial logistic regression analysis showed that obese subjects with T2DM had a gradually increasing risk for desirable (RO = 1.41, 95% CI 1.06-1.93, P = 0.027), insufficient (RO = 1.83, 95% CI 1.27-2.84, P < 0.001), or deficient ((RO = 2.14, 95% CI 1.15-3.75, P = 0.014) vitamin D levels. In obese subjects with T2DM, vitamin D levels correlated inversely with the risk indicators for diabetes, such as the levels of HbA1c (β = -0.16, P = 0.002), fasting insulin (Fins; β = -0.31, P = 0.008), and HOMA-IR (β = -0.19, P < 0.001). In obese subjects without T2DM, vitamin D was associated negatively with the risk of having T2DM at five-year follow-up (relative risk = 0.93, 95% CI 0.79-0.97, P = 0.037).

Conclusion

This study demonstrates that low vitamin D levels correlate with the presence of T2DM in the obese population. This finding indicates that hypovitaminosis D may be a potential biological vulnerability factor for the development of T2DM in obese subjects.

Mitigating diabetes-related complications: Empowering metformin with cholecalciferol and taurine supplementation in type 2 diabetic rats

BACKGROUND

Type 2 diabetes is one of the most prevalent chronic diseases worldwide, significantly impacting patients' quality of life. Current treatment options like metformin (MET) effectively counteract hyperglycemia but fail to alleviate diabetes-associated complications such as retinopathy, neuropathy, nephropathy, hepatopathy, and cardiovascular diseases.

AIM

To propose the supplementation of cholecalciferol (CHO) and taurine (TAU) to enhance MET efficacy in controlling diabetes while minimizing the risk of associated complications.

METHODS

The study involved sixty rats, including ten non-diabetic control rats and fifty experimental rats with type 2 diabetes induced by streptozotocin. The experimental rats were further subdivided into positive control and treatment subgroups. The four treatment groups were randomly allocated to a single MET treatment or MET combined with supplements either CHO, TAU, or both.

RESULTS

Diabetic rats exhibited elevated levels of glucose, insulin, Homeostasis Model Assessment of Insulin Resistance (HOMA-IR), glycated hemoglobin%, lipid markers, aspartate aminotransferase, and malondialdehyde, along with reduced levels of antioxidant enzymes (catalase and superoxide dismutase). The administration of CHO and TAU supplements alongside MET in diabetic rats led to a noticeable recovery of islet mass. The antioxidative, anti-inflammatory, and anti-apoptotic properties of the proposed combination therapy significantly ameliorated the aforementioned abnormalities.

CONCLUSION

The supplementation of CHO and TAU with MET showed the potential to significantly improve metabolic parameters and protect against diabetic complications through its antioxidative, anti-inflammatory, and anti-apoptotic effects.

Vitamin D supplementation for women during pregnancy

BACKGROUND

Vitamin D supplementation during pregnancy may help improve maternal and neonatal health outcomes (such as fewer preterm birth and low birthweight babies) and reduce the risk of adverse pregnancy outcomes (such as severe postpartum haemorrhage).

OBJECTIVES

To examine whether vitamin D supplementation alone or in combination with calcium or other vitamins and minerals given to women during pregnancy can safely improve certain maternal and neonatal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Trials Register (which includes results of comprehensive searches of CENTRAL, MEDLINE, Embase, CINAHL, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform, and relevant conference proceedings) (3 December 2022). We also searched the reference lists of retrieved studies.

SELECTION CRITERIA

Randomised and quasi-randomised trials evaluating the effect of supplementation with vitamin D alone or in combination with other micronutrients for women during pregnancy in comparison to placebo or no intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently i) assessed the eligibility of studies against the inclusion criteria, ii) assessed trustworthiness based on pre-defined criteria of scientific integrity, iii) extracted data from included studies, and iv) assessed the risk of bias of the included studies. We assessed the certainty of the evidence using the GRADE approach.

MAIN RESULTS

The previous version of this review included 30 studies; in this update, we have removed 20 of these studies to 'awaiting classification' following assessments of trustworthiness, one study has been excluded, and one new study included. This current review has a total of 10 included studies, 117 excluded studies, 34 studies in awaiting assessment, and seven ongoing studies. We used the GRADE approach to assess the certainty of the evidence. This removal of the studies resulted in evidence that was downgraded to low-certainty or very low-certainty due to study design limitations, inconsistency between studies, and imprecision. Supplementation with vitamin D compared to no intervention or a placebo A total of eight studies involving 2313 pregnant women were included in this comparison. We assessed four studies as having a low risk of bias for most domains and four studies as having high risk or unclear risk of bias for most domains. The evidence is very uncertain about the effect of supplementation with vitamin D during pregnancy compared to placebo or no intervention on pre-eclampsia (risk ratio (RR) 0.53, 95% confidence interval (CI) 0.21 to 1.33; 1 study, 165 women), gestational diabetes (RR 0.53, 95% CI 0.03 to 8.28; 1 study, 165 women), preterm birth (< 37 weeks) (RR 0.76, 95% CI 0.25 to 2.33; 3 studies, 1368 women), nephritic syndrome (RR 0.17, 95% CI 0.01 to 4.06; 1 study, 135 women), or hypercalcaemia (1 study; no cases reported). Supplementation with vitamin D during pregnancy may reduce the risk of severe postpartum haemorrhage; however, only one study reported this outcome (RR 0.68, 95% CI 0.51 to 0.91; 1 study, 1134 women; low-certainty evidence) and may reduce the risk of low birthweight; however, the upper CI suggests that an increase in risk cannot be ruled out (RR 0.69, 95% CI 0.44 to 1.08; 3 studies, 371 infants; low-certainty evidence). Supplementation with vitamin D + calcium compared to no intervention or a placebo One study involving 84 pregnant women was included in this comparison. Overall, this study was at moderate to high risk of bias. Pre-eclampsia, gestational diabetes, and maternal adverse events were not reported. The evidence is very uncertain about the effect of supplementation with vitamin D and calcium on preterm birth (RR not estimable; very low-certainty evidence) or for low birthweight (RR 1.45, 95% CI 0.14 to 14.94; very low-certainty evidence) compared to women who received placebo or no intervention. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D) One study involving 1298 pregnant women was included in this comparison. We assessed this study as having a low risk of bias in all domains. Pre-eclampsia was not reported. The evidence is very uncertain about the effect of supplementation with vitamin D, calcium, and other vitamins and minerals during pregnancy compared to no vitamin D on gestational diabetes (RR 0.42, 95% CI 0.10 to 1.73; very low-certainty evidence), maternal adverse events (hypercalcaemia no events and hypercalciuria RR 0.25, 95% CI 0.02 to 3.97; very low-certainty evidence), preterm birth (RR 1.04, 95% CI 0.68 to 1.59; low-certainty evidence), or low birthweight (RR 1.12, 95% CI 0.82 to 1.51; low-certainty evidence).

AUTHORS' CONCLUSIONS

This updated review using the trustworthy assessment tool removed 21 studies from the previous update and added one new study for a total of 10 included studies. In this setting, supplementation with vitamin D alone compared to no intervention or a placebo resulted in very uncertain evidence on pre-eclampsia, gestational diabetes, preterm birth, or nephritic syndrome. It may reduce the risk of severe postpartum haemorrhage; however, only one study reported this outcome. It may also reduce the risk of low birthweight; however, the upper CI suggests that an increase in risk cannot be ruled out. Supplementation with vitamin D and calcium versus placebo or no intervention resulted in very uncertain evidence on preterm birth and low birthweight. Pre-eclampsia, gestational diabetes, and maternal adverse events were not reported in the only study included in this comparison. Supplementation with vitamin D + calcium + other vitamins and minerals versus calcium + other vitamins and minerals (but no vitamin D) resulted in very uncertain evidence on gestational diabetes and maternal adverse events (hypercalciuria) and uncertain evidence on preterm birth and low birthweight. Pre-eclampsia was not reported in the only study included in this comparison. All findings warrant further research. Additional rigorous, high-quality, and larger randomised trials are required to evaluate the effects of vitamin D supplementation in pregnancy, particularly in relation to the risk of maternal adverse events.

Correlation between initial serum 25-hydroxyvitamin D and granulation growth in diabetic foot ulcers

OBJECTIVE

To determine the correlation between initial serum 25-hydroxyvitamin D (25(OH)D) levels with granulation growth in diabetic foot ulcers (DFUs) after 21 days of treatment.

METHOD

This cohort study involved patients with type 2 diabetes who had a DFU treated at hospital. Blood samples were taken from patients on admission. The chemiluminescent immunoassay technique was used to measure 25(OH)D levels. Granulation tissue growth was analysed by comparing the photographs from the initial treatment to day 21 of treatment.

RESULTS

The median value of 25(OH)D levels at initial treatment was 8 ng/ml. The result showed no correlation between 25(OH)D levels and the granulation growth in DFUs (p=0.86).

CONCLUSION

The initial serum 25(OH)D level was not correlated with the growth of granulation tissue in DFUs.

Mediating Effect of Insulin-Like Growth Factor-I Underlying the Link Between Vitamin D and Gestational Diabetes Mellitus

Vitamin D was well-known to be associated with gestational diabetes mellitus (GDM). Insulin-like growth factor-I (IGF-I) has been linked to vitamin D and GDM, respectively. We hypothesize that changes in IGF-I metabolism induced by 25(OH)D3 might contribute to GDM. Therefore, we investigated the independent and combined relationships of serum 25(OH)D3 and IGF-I concentrations with GDM risk, and the mediation effect of IGF-I on 25(OH)D3. A total of 278 pregnant women (including 125 cases and 153 controls) were recruited in our current study. Maternal serum 25(OH)D3 and IGF-I were measured in the second trimester. Logistic regression models were used to estimate the associations of 25(OH)D3 and IGF-I concentrations with the risk of GDM. Mediation analyses were used to explore the mediation effect of IGF-I on the association between 25(OH)D3 and the risk of GDM. After adjusted for the confounded factors, both the third and fourth quartile of 25(OH)D3 decreased the risk of GDM (OR = 0.226; 95% CI, 0.103-0.494; OR = 0.109; 95% CI, 0.045-0.265, respectively) compared to the first quartile of 25(OH)D3. However, the third and fourth quartile of serum IGF-I (OR = 5.174; 95% CI, 2.287-11.705; OR = 12.784; 95% CI, 5.292-30.879, respectively) increased the risk of GDM compared to the first quartile of serum IGF-I. Mediation analyses suggested that 19.62% of the associations between 25(OH)D3 and GDM might be mediated by IGF-I. The lower concentration of serum 25(OH)D3 or higher IGF-I in the second trimester was associated with an increased risk of GDM. The serum IGF-I level might be a potential mediator between 25(OH)D3 and GDM.

Effect of different nutrients on blood glucose, inflammatory response and oxidative stress in gestational diabetes mellitus: a network meta-analysis

We searched PubMed, Web of Science, Embase, The Cochrane Library, China Biomedical Literature Database and other databases from inception to June 2023. The included studies were randomised controlled trials (RCT). The studies were screened by four authors, divided into two independent pairs. A total of eighteen studies were included, including 1362 patients, involving twelve intervention measures. The different nutrients had a significant effect on improving blood glucose, reducing inflammation levels and reducing oxidative stress compared with placebo (P < 0.05). Cumulative probability ranking showed that vitamin A + vitamin D + vitamin E ranked first in lowering fasting blood glucose (standardised mean difference (SMD) = 41.30, 95 % CI (2.07, 825.60)) and postprandial 2-h blood glucose (SMD = 15.19, 95 % CI (4.16, 55.53)). In terms of insulin resistance index, the first highest probability ranking is vitamin D (SMD = 5.12, 95 % CI (0.76, 34.54)). In terms of reducing the high-sensitivity C-reactive protein level, the first in probability ranking is VE (SMD = 2.58, 95 % CI (1.87,3.55)). The results of cumulative probability ranking showed that Mg + Zn + Ca + VD ranked first in reducing TNF-α (SMD = 1.90, 95% CI (0.40, 9.08)) and IL-6 (SMD = 1.83, 95 % CI (0.37, 9.12)). In terms of reducing malondialdehyde levels, the first ranked probability is VB1 (SMD = 4.99, 95 % CI (1.85, 13.46)). Cumulative probability ranking results showed that Ca + VD ranked first in reducing total antioxidant capacity (SMD = 0.66,95 % CI (0.38, 1.15)) and glutathione (SMD = 1.39, 95 % CI (0.43, 4.56)). In conclusion, nutritional interventions have significant effects on improving blood glucose, inflammatory levels and oxidative stress in patients with gestational diabetes. Due to the high uncertainty in the results and differences in the number and quality of studies included, the reliability of the conclusions still needs to be validated by conducting large-sample, high-quality RCT studies.

Interventions in preconception and pregnant women at risk of gestational diabetes; a systematic review and meta-analysis of randomised controlled trials

BACKGROUND

Women at risk of gestational diabetes mellitus (GDM) need preventative interventions.

OBJECTIVE

To evaluate targeted interventions before and during pregnancy for women identified as being at risk of developing GDM.

METHODS

Systematic review and meta-analysis conducted following PRISMA guidelines. MEDLINE, EMBASE and the Cochrane Library in addition to reference and citation lists were searched to identify eligible randomised controlled trials (RCTs) utilising risk stratification during the preconception period or in the first/early second trimester. Screening and data extraction were carried out by the authors independently. Quality assessment was conducted based on the Cochrane risk-of-bias tool. Random effects meta-analysis and narrative synthesis were performed.

RESULTS

Eighty-four RCTs were included: two during preconception and 82 in pregnancy, with a pooled sample of 22,568 women. Interventions were behavioural (n = 54), dietary supplementation (n = 19) and pharmacological (n = 11). Predictive factors for risk assessment varied; only one study utilised a validated prediction model. Gestational diabetes was reduced in diet and physical activity interventions (risk difference - 0.03, 95% CI 0.06, - 0.01; I2 58.69%), inositol (risk difference - 0.19, 95% CI 0.33, - 0.06; I2 92.19%), and vitamin D supplements (risk difference - 0.16, 95% CI 0.25, - 0.06; I2 32.27%). Subgroup analysis showed that diet and physical activity interventions were beneficial in women with ≥ 2 GDM risk factors (risk difference - 0.16, 95% CI 0.25, - 0.07; I2 11.23%) while inositol supplementation was effective in women with overweight or obesity (risk difference - 0.17, 95% CI 0.22, - 0.11; I2 0.01%). Effectiveness of all other interventions were not statistically significant.

CONCLUSIONS

This review provides evidence that interventions targeted at women at risk of GDM may be an effective strategy for prevention. Further studies using validated prediction tools or multiple risk factors to target high-risk women for intervention before and during pregnancy are warranted.

Association between serum vitamin D levels and lipid profiles: a cross-sectional analysis

Vitamin D is an essential nutrient that plays a crucial role in calcium homeostasis and bone health. Recent research suggests that vitamin D may also have an impact on lipid metabolism, specifically the level of circulating lipids in the blood. We aim to investigate it role among healthy participate. We conducted a cross-sectional study of 15,600 patients who were referred to the laboratories of university hospitals. We measured the serum levels of Vitamin D as well as triglycerides, total cholesterol, LDL, and HDL using ELISA. We found that the mean serum level of Vitamin D was 40.31 ± 20.79 ng/mL. Of the participants, 16.7% had a serum level of Vitamin D less than 20 ng/mL, 57.7% had a level between 21 and 40 ng/mL, and 13.5% had a level between 41 and 60 ng/mL. Additionally, 12.2% had a level greater than 60 ng/mL. We performed a one-way analysis of variance and found that as the serum level of Vitamin D increased, the mean LDL level decreased significantly. Our study provides evidence of a significant relationship between serum levels of Vitamin D and LDL levels in patients. The findings suggest that vitamin D status may play a role in regulating lipid metabolism and may have implications for the prevention and treatment of cardiovascular disease. Further research is needed to elucidate the underlying mechanisms of this relationship and to determine optimal levels of vitamin D intake for maintaining lipid profiles.

The Effect of Vitamin D Supplementation on Lipid Profiles: an Umbrella Review of Meta-Analyses

According to published meta-analyses, vitamin D exerts different beneficial effects in preventing and controlling risk factors associated with noncommunicable chronic diseases; however, the results are still conflicting. The purpose of this umbrella meta-analysis was to investigate the effect of vitamin D supplementation on low-density lipoprotein cholesterol, high-density lipoprotein (HDL) cholesterol, total cholesterol (TC), and triglyceride (TG) as components of the lipid profile. PubMed, Scopus, Web of Science, and Cochrane Database of Systematic Reviews were systematically searched for meta-analyses of randomized controlled trials. The umbrella meta-analysis followed the PRISMA guidelines. The random-effects model was employed to estimate the overall effect size (ES). Overall, 25 meta-analyses were included. In the standardized mean difference analysis, vitamin D significantly decreased TG (ES: -0.15; 95% CI: -0.23, -0.08; P ≤ 0.001) and TC levels (ES: -0.17; 95% CI: -0.23, -0.11; P ≤ 0.001) and increased HDL levels (ES: 0.08; 95% CI: 0.01, 0.15; P = 0.025). In the weighted mean difference analysis, vitamin D significantly decreased only TG levels (ES: -4.63 mg/dL; 95% CI: -7.70, -1.57; P = 0.003). The present study supports that vitamin D supplementation could be considered a beneficial adjuvant therapy in managing lipid profile levels, especially in individuals with vitamin D deficiency. This systematic review was registered in PROSPERO as CRD42022306334.

The relationship between vitamin D deficiency and diabetic foot ulcer: A meta-analysis

A meta-analysis investigation to measure the relationship between vitamin D deficiency (VDD) and diabetic foot ulcer (DFU). A comprehensive literature inspection till February 2023 was applied and 1765 interrelated investigations were reviewed. The 15 chosen investigations enclosed 2648 individuals with diabetes mellitus in the chosen investigations' starting point, 1413 of them were with DFUs, and 1235 were without DFUs. Odds ratio (OR) in addition to 95% confidence intervals (CIs) were used to compute the value of the relationship between VDD and DFU by the dichotomous and continuous approaches and a fixed or random model. Individuals with DFUs had significantly lower vitamin D levels (VDL) (MD, -7.14; 95% CI, -8.83 to -5.44, P < 0.001) compared to those without DFU individuals. Individuals with DFUs had a significantly higher number of VDD individuals (OR, 2.27; 95% CI, 1.63-3.16, P < 0.001) compared to those without DFU individuals. Individuals with DFU had significantly lower VDL and a significantly higher number of VDD individuals compared to those without DFU individuals. However, caused of the small sample sizes of several chosen investigations for this meta-analysis, care must be exercised when dealing with its values.

Effect of vitamin D supplementation on glucose control in mid-late gestation: A randomized controlled trial

BACKGROUND & AIMS

It is unclear whether vitamin D supplementation contributes to gestational glucose control and whether the specific effects vary in individuals with diverse genetic and metabolic contexts. The study aimed to assess the effect of vitamin D supplementation during pregnancy on subsequent glucose levels and to identify factors modulating the response to vitamin D3 intake.

METHODS

We conducted a multicenter randomized controlled trial, 1720 pregnant women recruited from the three antenatal clinics of Hefei city, China, who were allocated to receive either 1600 IU/d vitamin D3 (n = 858) or 400 IU/d vitamin D3 (n = 862) for 2 months at 24-28 weeks' gestation. Outcomes were changes in serum 25-hydroxyvitamin D (25(OH)D) and fasting plasma glucose (FPG) levels from baseline, 32-36 weeks' gestation to delivery (37-41 weeks) quantified using a linear mixed model.

RESULTS

After 2 months, FPG levels of the control group significantly increased by 0.22 mmol/L (from 4.6 [0.4] mmol/L to 4.8 [1.2] mmol/L, P < 0.001) at delivery, but that of the intervention group had no significant variation (from 4.6 [0.4] mmol/L to 4.7 [1.1] mmol/L; between-group difference in changes, -0.2 mmol/L, 95% CI, -0.3 to -0.08, P = 0.015). And differences in FPG variation were found in participants with the ApaI SNP CC genotype, or BsmI-CC, TaqI-AA, FokI-AA, respectively. Pregnant women with basal 25(OH)D concentrations higher than 50 nmol/L subgroup showed the greatest decline in FPG levels (between-group difference, -0.3 mmol/L; 95% CI, -0.5 to -0.1, P < 0.001). Moreover, pregnant women with GDM, multiple pregnancies or who were overweight were more likely to have FPG decline from vitamin D treatment.

CONCLUSIONS

Vitamin D supplementation significantly protected glucose homeostasis in mid-late gestation, and glycemic response to vitamin D may be dependent on basal 25(OH)D status, VDR gene polymorphism or their metabolic profiles.

TRIAL REGISTRATION NUMBER

ChiCTR2100051914. URL OF REGISTRATION: http://www.chictr.org.cn/showproj.aspx?proj=134700.

Vitamin D in pregnancy (GRAVITD) - a randomised controlled trial identifying associations and mechanisms linking maternal Vitamin D deficiency to placental dysfunction and adverse pregnancy outcomes - study protocol

BACKGROUND

The prevalence of vitamin D deficiency is high among pregnant women. Vitamin D deficiency in pregnancy is associated with increased risk of adverse pregnancy outcomes especially complications related to placental dysfunction and insulin resistance. The objective of this study is to investigate if a higher dose of vitamin D supplementation in pregnancy reduces the prevalence of vitamin D deficiency and prevents adverse pregnancy outcome with special emphasize on preeclampsia, foetal growth restriction and gestational diabetes.

METHODS

GRAVITD is a double-blinded randomised trial with parallel groups where all pregnant women attending the free of charge national nuchal translucency scan programme in gestational week 10-14 at Randers Regional Hospital are invited to participate. Enrolment started in June 2020. Participants are randomised in a two armed randomization with a 1:1 allocation ratio into 1) control group - receives 10 µg of vitamin D or 2) intervention group - receives 90 µg of vitamin D. A total of 2000 pregnant women will be included. Maternal blood samples and questionnaires describing life-style habits are collected upon enrolment. For half of the participants blood samples and questionnaires will be repeated again in 3rd trimester. Blood samples will be analysed for 25-hydroxy-vitamin D using high-performance liquid chromatography coupled with tandem mass spectrometry. Upon delivery, placental tissue and umbilicalcord blood will be collected and information on maternal and fetal outcomes will be exstracted from medical records. The primary outcomes are serum levels of 25-hydroxy-vitamin D ≥ 75 nmol/L and the rate of preeclampsia, foetal growth restriction and gestational diabetes. Secondary outcome includes identification and impact on placental functions related to vitamin D. A tertiary outcome is to initiate a cohort of children born from mothers in the trial for future follow-up of the effects of vitamin D on childhood health.

DISCUSSION

Provided that this trial finds beneficial effects of a higher dose of vitamin D supplementation in pregnancies, official recommendations can be adjusted accordingly. This will provide a low-cost and easily implementable adjustment of prenatal care which can improve health for both mother and child during pregnancy and beyond.

TRIAL REGISTRATION

ClinicalTrial.gov: NCT04291313 . Registered February 17, 2020.

Association between vitamin D deficiency and diabetic foot ulcer wound in diabetic subjects: A meta-analysis

A meta-analysis was performed to evaluate the association between vitamin D deficiency and diabetic foot ulcer wounds in diabetic subjects. A systematic literature search up to March 2022 incorporated 7586 subjects with diabetes mellitus at the beginning of the study; 1565 were using diabetic subjects with foot ulcer wounds, and 6021 were non-ulcerated diabetic subjects. Statistical tools like the dichotomous and contentious method were used within a random or fixed-influence model to establish the odds ratio (OR) and mean difference (MD) with 95% confidence intervals (CIs) to evaluate the influence of vitamin D deficiency in managing diabetic foot ulcer wound. Diabetic subjects with foot ulcer wounds had significantly lower vitamin D levels (MD, -6.48; 95% CI, -10.84 to -2.11, P < .004), higher prevalence of vitamin D deficiency (<50 nmoL/L) (OR, 1.82; 95% CI, 1.32-2.52, P < .001), and higher prevalence of severe vitamin D deficiency (OR, 2.53; 95% CI, 1.65-3.89, P < .001) compared with non-ulcerated diabetic subjects. Diabetic subjects with foot ulcer wounds had significantly lower vitamin D levels, higher prevalence of vitamin D deficiency, and higher prevalence of severe vitamin D deficiency compared with non-ulcerated diabetic subjects. Further studies are required to validate these findings.

Vitamin D Supplementation for the Outcomes of Patients with Gestational Diabetes Mellitus and Neonates: A Meta-Analysis and Systematic Review

BACKGROUND

Prevention and timely treatment of gestational diabetes mellitus (GDM) are important to the prognosis of pregnant women and neonates. We aimed to conduct a meta-analysis to evaluate the effects and safety of vitamin D supplementation on GDM patients and neonates, to provide insights into clinical GDM treatment.

METHODS

Two authors searched the Medline, PubMed, Cochrane Library, Web of Science, Embase, CNKI, and Wanfang databases for randomized controlled trials (RCTs) on the effects and safety of vitamin D supplementation in GDM patients. The quality of the included RCTs was evaluated according to Cochrane handbook. RevMan 5.3 software was used for statistical analysis.

RESULTS

A total of 20 RCTs involving 1682 GDM patients were finally included, of whom 837 received vitamin D supplementation. Vitamin D supplementation in GDM patients increased the serum 25(OH)D level (SMD = 4.07, 95% CI: (2.73, 5.41)) and HDL level (SMD = 0.41, 95% CI: (0.23, 0.58)) and reduced serum LDL (SMD = -0.49, 95% CI: (-0.68, -0.29)), TG (SMD = -0.59, 95% CI: (-1.01, -0.17)), and TC (SMD = -0.67, 95% CI: (-1.19, -0.14)) levels in GDM patients (all P < 0.05). Besides, vitamin D supplementation reduced the risk of premature birth (OR = 0.37, 95% CI: (0.22, 0.62)), hyperbilirubinemia (OR = 0.38, 95% CI: (0.25, 0.58)), and neonatal hospitalization (OR = 0.38, 95% CI: (0.25, 0.58)) of neonates (all P < 0.05). No significant publication bias in synthesized results was found (all P > 0.05).

CONCLUSIONS

Vitamin D supplementation improves the blood lipid level in GDM patients and reduces adverse neonatal outcomes. The dose and duration of vitamin D supplementation for safety need to be further investigated in future high-quality studies.

Effect of supplementation with 5,000 IU of vitamin D on the glycemic profile of women with gestational diabetes mellitus

OBJECTIVES

The frequency of GDM and vitamin D insufficiency in Mexico is high. Vitamin D supplementation in GDM patients has shown favorable but non-homogeneous results regarding improvement of glycemic profile. The aim of the study was to assess the effects of supplementing with 5,000 IU of vitamin D on the glycemic profile of women with GDM.

METHODS

A randomized clinical trial was conducted on women with GDM who received 5,000 IU of vitamin D (n=27) or a placebo (n=27) for eight weeks. Changes in vitamin D levels and metabolic parameters before and after the intervention were analyzed.

RESULTS

Vitamin D vs. placebo: 25-OHD (32 vs. 26 ng/mL, p=0.006), HbA_1c (6.0 vs. 6.1%, p=0.29), glucose (99 vs. 87 mg/dL, p=0.29), insulin (14 vs. 13 µIU/mL, p=0.79), HOMA-IR (3.6 vs. 2.6, p=0.55), QUICKI (0.31 vs. 0.33, p=0.55).

CONCLUSIONS

Supplementation with 5,000 IU of vitamin D for eight weeks had no significant effect on the glycemic profile.

Sleep patterns modify the association of 25(OH)D with poor cardiovascular health in pregnant women

BACKGROUND

The relationship between vitamin D status and gestational cardiovascular health (CVH) is inconsistent in previous studies. Emerging evidence shows that sleep behaviors are related to vitamin D metabolism. However, no studies evaluate the interaction of vitamin D and sleep behaviors on gestational CVH.

OBJECTIVE

We aimed to estimate the relationship between 25-hydroxyvitamin D [25(OH)D] concentrations and gestational CVH, and whether the relationship was modified by sleep behaviors.

METHODS

The data of this study was from a multicenter birth cohort study. A total of 9,209 pregnant women at 16-23 weeks of gestation were included. 25(OH)D concentrations were measured from collected blood. Sleep patterns consisted of major sleep behaviors including duration, chronotype, insomnia, snoring, and excessive daytime sleepiness. Data on poor CVH was based on four "clinical" CVH metrics, including body mass index, blood pressure, total cholesterol, and glucose levels.

RESULTS

The proportion of women with poor CVH was 25.0%. The relative risk (RR) (95%CI) of poor CVH was 0.67 (0.58-0.76) in women with 25(OH)D ≥ 50 nmol/L after multivariate adjustments. Lower 25(OH)D concentrations were significantly associated with poor CVH. Such association was also evident in subgroups analysis. We found a significant interaction of 25(OH)D (P for interaction = 0.01) with sleep patterns on the risk of poor CVH. A negative dose-response relation was observed between 25(OH)D concentrations and poor CVH risk in healthy or intermediate sleep, not poor sleep. 25(OH)D concentrations were lower and the risk of poor CVH was higher in pregnant women with poor sleep patterns (P < 0.05).

CONCLUSION

Our study suggests that sleep patterns modify the association of 25(OH)D concentrations with the CVH among pregnant women.

The effect of vitamin D supplementation on oxidative stress and inflammatory biomarkers in pregnant women: a systematic review and meta-analysis of clinical trials

BACKGROUND

Vitamin D deficiency, a common problem among pregnant women, is linked with maternal inflammation, oxidative stress and consequent adverse pregnancy outcomes. The aim of this systematic review was to evaluate the effect of vitamin D supplementation on oxidative stress and inflammatory biomarkers in pregnant women according to the PRISMA guidance.

METHODS

Four databases including PubMed/MEDLINE, Scopus, Web of Science and Cochrane were used for searching papers published until 25th July 2022. Clinical trials that assessed 25-Hydroxyvitamin D (25(OH)D), inflammatory markers (including high sensitivity C-reactive protein (hs-CRP) and certain cytokines) and oxidative stress markers (including malondialdehyde (MDA), total antioxidant capacity (TAC) and glutathione (GSH)) in pregnant women, were included in this review. The primary search of three databases displayed 21571 records. After removing duplicates and irrelevant articles, 17 eligible RCTs included for more evaluation. Random effect model and Der Simonian-Laird method were used to pool the data of studies. Risk of bias assessed according to version 2 of the Cochrane risk-of-bias tool for randomized trials.

RESULTS

According to the meta-analysis result, vitamin D supplementation caused a significant increase in the maternal circulating concentrations of 25(OH)D (SMD 2.07; 95%, CI 1.51, 2.63; p < 0.001), TAC (SMD 2.13, 95% CI 1.04 to 3.23, p < 0.001) and GSH (SMD 4.37, 95% CI 2.9 to 5.74, p < 0.001) as well as a significant decrease in the levels of MDA (SMD -0.46, 95% CI -0.87 to -0.05, p = 0.02). However, it had no significant impact on hs-CRP concentrations (SMD 0.24; 95% CI, -0.55, 1.03; p = 0.50).

CONCLUSION

In the present study, vitamin D supplementation led to increased levels of 25(OH)D, TAC and GSH and also decreased concentration of MDA. Nevertheless, because of low certainty of evidence, these findings have to be declared conservatively.

TRIAL REGISTRATION

Registration code in PROSPERO website: CRD42020202600.

Early pregnancy vitamin D insufficiency and gestational diabetes mellitus

OBJECTIVES

To test the hypothesis that a link existed between vitamin D levels in the first trimester and gestational diabetes mellitus (GDM).

METHODS

The 25-hydroxyvitamin D₃ levels were tested in the first trimester and pregnant outcomes were followed up in 1726 women.

RESULTS

Only 5.9% of pregnant women have sufficient 25(OH)D₃ . More women with GDM are in the status of 25(OH)D₃ insufficiency than women with normal glucose tolerance (NGT) (p < 0.05). Age (odds ratio [OR]: 1.047, 95% confidence interval [CI]: 1.014-1.081), pre-pregnancy body mass index (BMI) (OR: 1.132, 95%CI: 1.092-1.173) were risk factors of GDM while 25-(OH) D₃ (OR: 0.979, 95%CI: 0.960-0.999) was a protective factor. After adjusted for maternal age and pre-pregnancy BMI, 25(OH)D₃ insufficiency (<30 ng/mL) is an independent predictor of GDM (OR: 2.122, 95%CI: 1.084-4.155); 25(OH)D₃ level correlated with fasting blood glucose in the first trimester negatively.

CONCLUSION

Vitamin D insufficiency in early pregnancy was significantly associated with an increased risk for GDM in Chinese women.

Paricalcitol Attenuates Metabolic Syndrome-Associated Heart Failure through Enhanced Mitochondrial Fusion

Objectives

Transition from cardiac hypertrophy to failure involves adverse metabolic reprogramming involving mitochondrial dysfunction. We have earlier shown that vitamin D deficiency induces heart failure, at least in part, through insulin resistance. However, whether activation of vitamin D receptor (VDR) can attenuate heart failure and underlying metabolic phenotype requires investigation. Thus, we aimed to assess the cardioprotective potential of paricalcitol, a vitamin D receptor-activator, against cardiac hypertrophy and failure in high-fat high-fructose-fed rats.

Methods

Male Sprague Dawley rats were fed control (Con) or high-fat high-fructose (HFHFrD) diet for 20 weeks. After 12 weeks, rats from HFHFrD group were divided into the following: HFHFrD, HFHFrD+P (paricalcitol i.p. 0.08 μg/kg/day) and HFHFrD+E (enalapril maleate i.p. 10 mg/kg/day). Intraperitoneal glucose tolerance test, blood pressure measurement, and 2D echocardiography were performed. Cardiac fibrosis was assessed by Masson's trichrome staining of paraffin-embedded heart sections. Mitochondrial DNA and proteins, and citrate synthase activity were measured in rat hearts. VDR was silenced in H9c2 cardiomyoblasts, and immunoblotting was performed.

Results

Paricalcitol improved glucose tolerance, serum lipid profile, and blood pressure in high-fat high-fructose-fed rats. Paricalcitol reduced cardiac wall thickness and increased ejection fraction in high-fat high-fructose-fed rats but had no effect on perivascular fibrosis. PGC1-α was upregulated in the HFHFrD+P group compared to the HFHFrD group, but there was no significant difference in mitochondrial content. Citrate synthase activity was significantly higher in the HFHFrD+P group compared to the HFHFrD group. Rat hearts of the HFHFrD+P group had significantly higher expression of mitofusins. H9c2 cells with VDR knockdown showed significantly lower expression of Mfn2. Improvement in the HFHFrD+P group was comparable with that in the HFHFrD+E group.

Conclusions

Paricalcitol reverses cardiac dysfunction in rats with metabolic syndrome by enhancing mitochondrial fusion. We demonstrate repurposing potential of the drug currently used in end-stage kidney disease.

Participant attrition and perinatal outcomes in prenatal vitamin D-supplemented gestational diabetes mellitus patients in Asia: A meta-analysis

BACKGROUND

The role of vitamin D supplementation in gestational diabetes mellitus (GDM) patients is unclear.

AIM

To determine the burden and risk of post-randomization GDM patient attrition from vitamin D-supplemented arms of randomized controlled trials (RCTs). The auxiliary aim was to compare the effects of nutritional supplements on their fasting blood glucose (FPG) levels and perinatal outcomes.

METHODS

RCTs were searched in the PubMed, Embase, and Scopus databases. Random-effect prevalence and pairwise meta-analysis were performed for the primary objective. The auxiliary aim was to compare the effects of nutritional supplements on their fasting blood glucose (FPG) levels and perinatal outcomes. Fixed-effect network meta-analyses were undertaken for the secondary goals. All analyses were performed using Stata software, and statistical significance was determined at P < 0.05.

RESULTS

Thirteen RCTs from Iran and China were reviewed. The participant attrition burden in vitamin D recipients was 6% [95% confidence interval (CI): 0.03, 0.10], and its risk did not vary from non-recipients. Vitamin D and calcium co-supplementation reduced the cesarean section incidence in GDM patients [risk ratio (RR): 0.37; 95%CI: 0.18, 0.74]. The hyperbilirubinemia or hospitalization risk in their newborns decreased with vitamin D supplementation (RR: 0.47; 95%CI: 0.27, 0.83) and co-supplementation with calcium (RR: 0.35; 95%CI: 0.16, 0.77) or omega-3 fatty acids (RR: 0.25; 95%CI: 0.08, 0.77). Vitamin D and probiotics co-supplementation decreased newborn hyperbilirubinemia risk (RR: 0.28; 95%CI: 0.09, 0.91). FPG levels and macrosomia risk did not vary across interventions.

CONCLUSION

In RCTs, vitamin D supplementation or co-supplementation in GDM patients showed a low participant attrition burden and low risk of cesarean section, newborn hyperbilirubinemia, and newborn hospitalization.

The Association Between Vitamin D and Type 2 Diabetes Mellitus Complicated with Non-Alcoholic Fatty Liver Disease: An Observational Cross-Sectional Study

OBJECTIVE

To investigate the association between vitamin D deficiency and NAFLD risk in patients with type 2 diabetes mellitus (T2DM).

METHODS

Overall, 434 patients with T2DM admitted to Hebei General Hospital from January 2019 to December 2019 were selected as the study subjects. According to abdominal ultrasound findings, patients were divided into the NAFLD group and the non-NAFLD group. Participants were divided into two study groups according to the 25-hydroxyvitamin D [25(OH)D] level. 25(OH)D deficiency was defined if 25(OH)D vitamin levels were <20 ng/mL. Chi-square test and one-way analysis of variance were used to compare groups. The relationship between 25(OH)D and NAFLD risk was analyzed using correlation and regression analyses. Furthermore, subgroup analyses were performed to verify the robustness of the results.

RESULTS

The 25(OH)D level in patients with T2DM complicated by NAFLD was significantly lower than in patients with T2DM only. Vitamin D deficiency was highly prevalent among T2DM patients with NAFLD. This study suggested that vitamin D deficiency was an independent factor for developing NAFLD in patients with T2DM. T2DM patients with vitamin D deficiency had 2.045 times higher risk of developing NAFLD than those without vitamin D deficiency. Vitamin D deficiency was associated with high NAFLD preference in T2DM patients with BMI >23kg/m², but not those with BMI ≤23kg/m². The significant correlation between vitamin D deficiency and NAFLD was found in participants with BMI >23kg/m², age ≤65 years, without hypertension, TG <1.7mmol/l, HDL ≥1 mmol/l in men, ≥1.3 mmol/l in women, HBA1C ≤7%, or females.

CONCLUSION

This study suggests that T2DM people with BMI >23kg/m² were more susceptible to NAFLD by vitamin D deficiency and that it is necessary to maintain optimal serum vitamin D levels in this population.

Changes in anthropometric and blood 25-hydroxyvitamin D measurements in antenatal vitamin supplemented gestational diabetes mellitus patients: a systematic review and meta-analysis of randomized controlled trials

Objective:

Gestation weight (GW), body mass index (BMI), and blood 25-hydroxyvitamin D [25(OH)D] level during pregnancy are important determinants of the gestational outcomes. This study aimed to study how these parameters vary between antenatal vitamin D recipients and non-recipients in gestational diabetes mellitus (GDM) patients.

Material and Methods:

The randomized controlled trials comparing these outcomes between vitamin D recipient and non-recipient GDM patients were searched in electronic databases (PubMed, Embase, and Scopus). The reviewed studies’ data were abstracted and critically appraised using the Cochrane tool. The estimation of the weighted mean difference for GW and BMI and standardized mean difference (SMD) for 25(OH)D levels occurred by juxtaposing the interventions meta-analytically (random-effect model). The statistical inconsistency was determined by Chi² and I² method. The statistical significance was estimated at p<0.05 and 95% confidence interval (CI).

Results:

Eleven eligible trials (all Iran-based, except one), sourcing data from about 875 GDM patients, were reviewed. Overall, the risk of bias was low, except for selection and performance bias. On random-effect model meta-analysis, the 25(OH)D levels of the GDM patients favored the vitamin D recipients when compared to non-vitamin D (SMD 1.97, 95% CI: 1.06-2.88, p<0.001; I² 96.2%, p of Chi² <0.001) and placebo (SMD 1.86, 95% CI: 0.95-2.77, p<0.001; I² 95.3%, p of Chi² <0.001) recipients, respectively. On meta-regression, sample size was a predictor of the observed heterogeneity. For GW and BMI the interventions did not differ statistically significantly.

Conclusion:

In GDM patients, antenatal use of vitamin D aids in the rise of blood 25(OH)D levels. However, vitamin D supplementation did not affect change in GW or BMI.

Effects of Calcium and Vitamin D Co-supplementation on the Lipid Profile: A Systematic Review and Meta-analysis

PURPOSE

Calcium and vitamin D co-supplementation is common and widely used, but randomized, controlled trials (RCTs) have yielded inconclusive results concerning its impact on the serum lipid profile.

METHODS

A comprehensive literature search of Medline, Web of Science, Scopus, Embase, Cochrane Central Register of Controlled Trials, and clinical trial registry databases was conducted to identify placebo-controlled RCTs that were published through September 2020 and that evaluated the impact of calcium and vitamin D co-supplementation on total cholesterol (TC), triglycerides (TGs), low- and very-low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol (HDL-C). Standardized mean differences (SMDs) were pooled using random-effects meta-analysis models.

FINDINGS

Thirteen studies in a total of 2304 participants met the inclusion criteria. Calcium and vitamin D co-supplementation was associated with significant reductions in both TC (SMD, -0.81; 95% CI, -1.35 to -0.27; I² = 94.6%) and TGs (SMD, -0.50; 95% CI, -0.91 to -0.08; I² = 91.5%), and with a significant increase in HDL-C (SMD, 1.22; 95% CI, 0.60 to 1.83; I² = 95.4%). However, calcium and vitamin D co-supplementation were not found to be associated with significantly decreased low-density lipoprotein cholesterol (SMD, -0.39; 95% CI, -0.78 to 0.01; I² = 90.1%) or very-low-density lipoprotein cholesterol (SMD, -0.01; 95% CI, -0.70 to 0.69; I² = 82.3%).

IMPLICATIONS

The findings from the present systematic review and meta-analysis suggest that calcium and vitamin D co-supplementation has a beneficial effect on TC, TG, and HDL-C. Larger-scale, well-designed RCTs are needed to clarify the effect of calcium and vitamin D co-supplementation on all lipid-profile components.

Independent and Combined Effects of Calcium and Vitamin D Supplementation on Blood Lipids in Overweight or Obese Premenopausal Women: A Triple-Blind Randomized Controlled Clinical Trial

Background:

Dyslipidemia is often associated with obesity and contributes to the increased risk of atherosclerosis, heart disease, and stroke. This study was designed to evaluate the independent or combined effect of calcium and vitamin D (Ca + Vit D) supplementation on blood lipid profile in overweight or obese premenopausal women.

Methods:

This study is a triple-blind, randomized, parallel, placebo-controlled trial. About 100 overweight or obese (body mass index (BMI) of 25–40 kg/m²) premenopausal (aged 30–50 years) women, recruited from Shiraz University of Medical Sciences (SUMS) clinics, were allocated into 4 groups: (1) calcium (Ca) supplementation (2 tablets per day; each containing 500 mg calcium carbonate), (2) vitamin D (Vit D) supplementation (2 tablets per day; each containing 200 IU vitamin D3), (3) Ca + Vit D supplementation (2 tablets per day; each containing 500 mg calcium carbonate plus 200 IU vitamin D3), (4) placebo supplementation (2 tablets per day, containing micro-cellulose). All participants received a 500 kcal energy-restricted diet. Blood lipids, serum vitamin D, and anthropometric indices were measured at baseline and after 8 weeks. Physical activity and 3-day dietary records were taken at baseline and every 4 weeks during the intervention.

Results:

At 8 weeks, triglyceride levels were significantly decreased in the Ca group (P = 0.002). Low-density lipoprotein (LDL) levels were decreased in the Ca + Vit D group (P = 0.04) and high-density lipoprotein (HDL) levels decreased in both the Ca and Ca + Vit D groups (P = 0.006, P = 0.004, respectively). The results of one-way ANOVA indicated that changes in the serum lipid profile levels were not significantly different among the four groups (P = 0.90, P = 0.86, P = 0.61, P = 0.27, and P = 0.19, respectively for TG, TC, LDL, HDL, and LDL/HDL). The results were not significant even after adjusting for potential covariates.

Conclusions:

Although the results were not significantly different among the four treated groups at 8 weeks, within-group changes like the reduction in triglyceride and LDL levels, respectively in the Ca group and Ca + Vit D group, and HDL levels in both the Ca and Ca + Vit D groups were significant. These changes may have potentially significant public health implications.

The Effect of Dietary Supplements on Oxidative Stress in Pregnant Women with Gestational Diabetes Mellitus: A Network Meta-Analysis

BACKGROUND

Gestational diabetes mellitus (GDM) exacerbates the oxidative stress status of the pregnant women. Τo improve the oxidative stress status, several therapeutic interventions have been suggested. The aim of this network meta-analysis is to assess the effect of different dietary supplements on the oxidative stress status in pregnant women with GDM.

METHODS

A network meta-analysis of randomized control trials was performed comparing the changes delta (Δ) in total antioxidant capacity (TAC) and concentration of malondialdehyde (MDA) as primary outcomes, following different therapeutic interventions with dietary supplements in pregnant women with GDM. Four electronic databases and grey literature sources were searched. The secondary outcomes were other markers of oxidative stress.

RESULTS

The meta-analysis included 16 studies of 1173 women with GDM. Regarding ΔTAC: probiotics and omega-3 with vitamin E were superior to placebo/no intervention. Regarding ΔMDA: vitamin D with calcium, omega-3, vitamin D, omega-3 with vitamin E, magnesium with zinc and calcium, and probiotics were superior to placebo/no intervention.

CONCLUSIONS

Administration of dietary supplements in women with GDM can be helpful in limiting the oxidative stress which develop in these pregnancies.

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus

BACKGROUND

The effects of vitamin and mineral supplementation on women with gestational diabetes mellitus (GDM) have not been well established. We conduct a meta-analysis to evaluate the effects of vitamin and mineral supplementation on glycemic control, inflammation and oxidative stress for women with GDM.

METHODS

A systematic search of randomized controlled trials (RCTs) was conducted from PubMed, Embase, Web of Science and Cochrane Library up to July, 2020. Various results were pooled by using Review manager 5.3 and Stata 12.0. Mean difference (MD) with 95% confidence interval (CI) was estimated. Heterogeneity between studies was assessed by I-squared (I²) tests.

RESULTS

Six hundred ninety-eight patients from 12 trials were included in our meta-analysis. Magnesium, zinc, selenium, calcium, vitamin D and E (alone or in combination) were found to significantly improve glycemic control in women with GDM compared to those receiving placebos: fasting plasma glucose (FPG) (MD = - 9.02; 95% CI: - 12.09, - 5.96; P < 0.00001), serum insulin (MD = - 4.33; 95% CI: - 5.35, - 3.32; P < 0.00001), homeostasis model assessment-insulin resistance (HOMA-IR) (MD = - 1.34; 95% CI: - 1.60, - 1.07; P < 0.00001), and homeostasis model of assessment for β cell function (HOMA-B) (MD = - 15.58; 95% CI: - 23.70, - 7.46; P = 0.0002). Vitamin and mineral supplementation was found to attenuated inflammation and oxidative stress through decreasing high-sensitivity C-reactive protein (hs-CRP) (MD = - 1.29; 95% CI: - 1.82, - 0.76; P < 0.00001), malondialdehyde (MDA) (MD = - 0.71; 95% CI: - 0.97, - 0.45; P < 0.00001), and increasing total antioxidant capacity (TAC) (MD = 45.55; 95% CI: 22.02, 69.08; P = 0.0001).

CONCLUSIONS

This meta-analysis shows that vitamin and mineral supplementation significantly improved glycemic control, attenuated inflammation and oxidative stress in women with GDM.

Vitamin D status and association with gestational diabetes mellitus in a pregnant cohort in Iceland

Background

Vitamin D deficiency has been associated with an increased risk of gestational diabetes mellitus (GDM), one of the most common pregnancy complications. The vitamin D status has never previously been studied in pregnant women in Iceland.

Objective

The aim of this research study was to evaluate the vitamin D status of an Icelandic cohort of pregnant women and the association between the vitamin D status and the GDM incidence.

Design

Subjects included pregnant women (n = 938) who attended their first ultrasound appointment, during gestational weeks 11-14, between October 2017 and March 2018. The use of supplements containing vitamin D over the previous 3 months, height, pre-pregnancy weight, and social status were assessed using a questionnaire, and blood samples were drawn for analyzing the serum 25‑hydroxyvitamin D (25OHD) concentration. Information regarding the incidence of GDM later in pregnancy was collected from medical records.

Results

The mean ± standard deviation of the serum 25OHD (S-25OHD) concentration in this cohort was 63±24 nmol/L. The proportion of women with an S-25OHD concentration of ≥ 50 nmol/L (which is considered adequate) was 70%, whereas 25% had concentrations between 30 and 49.9 nmol/L (insufficient) and 5% had concentrations < 30 nmol/L (deficient). The majority of women (n = 766, 82%) used supplements containing vitamin D on a daily basis. A gradual decrease in the proportion of women diagnosed with GDM was reported with increasing S-25OHD concentrations, going from 17.8% in the group with S-25OHD concentrations < 30 nmol/L to 12.8% in the group with S-25OHD concentrations ≥75 nmol/L; however, the association was not significant (P for trend = 0.11).

Conclusion

Approximately one-third of this cohort had S-25OHD concentrations below adequate levels (< 50 nmol/L) during the first trimester of pregnancy, which may suggest that necessary action must be taken to increase their vitamin D levels. No clear association was observed between the vitamin D status and GDM in this study.

Dietary supplementation for gestational diabetes prevention and management: a meta-analysis of randomized controlled trials

PURPOSE

The use of supplement to prevent and ease gestational diabetes (GDM) progression has been examined in various studies, but the results were inconclusive, and studies evaluated dietary supplements separately. The present review aimed to evaluate the efficacy of various dietary supplementation on GDM risk and the surrogate markers for cardiometabolic risk of pregnant women with GDM.

METHODS

A comprehensive search on multiple databases were performed to identify randomized controlled trials. Random-effects model was used to pool the results in relative risk (RR) or mean difference.

RESULTS

Fifty-three randomized controlled studies with 9443 pregnant women were included. Vitamin D (5 studies, RR 0.64; 95% CI 0.44, 0.94) and myo-inositol (4 studies, RR 0.34, 95% CI 0.20, 0.58) supplementation significantly reduced the risk of GDM. Myo-inositol, probiotics, and vitamin D showed significant intervention effect on surrogate markers related to glycemic control, lipid profile, inflammatory, and oxidative stress. However, the majority of included studies were clustered to Iran and Italy, which might convey a generalizability bias.

CONCLUSION

Dietary supplementation including vitamin D and myoinositol supplementation has the potential in primary prevention and management of GDM, whereas probiotics demonstrated its ability in GDM management by improving the levels of surrogate markers for cardiometabolic risk. The potential for dietary supplement in preventing GDM or managing cardiometabolic risk of pregnant women should receive more attentions.

Obesity-induced Vitamin D Deficiency Contributes to Lung Fibrosis and Airway Hyperresponsiveness

Vitamin D (VitD) has pleiotropic effects. VitD deficiency is closely involved with obesity and may contribute to the development of lung fibrosis and aggravation of airway hyperresponsiveness (AHR). We evaluated the causal relationship between VitD deficiency and the lung pathologies associated with obesity. In vivo effects of VitD supplementation were analyzed using high-fat diet (HFD)-induced obese mice and TGF-β1 (transforming growth factor-β1) triple transgenic mice. Effects of VitD supplementation were also evaluated in both BEAS-2B and primary lung cells from the transgenic mice. Obese mice had decreased 25-OH VitD and VitD receptor expressions with increases of insulin resistance, renin and angiotensin-2 system (RAS) activity, and leptin. In addition, lung pathologies such as a modest increase in macrophages, enhanced TGF-β1, IL-1β, and IL-6 expression, lung fibrosis, and AHR were found. VitD supplementation to HFD-induced obese mice recovered these findings. TGF-β1-overexpressing transgenic mice enhanced macrophages in BAL fluid, lung expression of RAS, epithelial-mesenchymal transition markers, AHR, and lung fibrosis. VitD supplementation also attenuated these findings in addition to the attenuation of the expressions of TGF-β1, and phosphorylated Smad-2/3 in lung. Supplementing in vitro-stimulated BEAS-2B and primary lung cells with VitD inhibited TGF-β1 expression, supporting the suppressive effect of VitD for TGF-β1 expression. These results suggest that obesity leads to VitD deficiency and worsens insulin resistance while enhancing the expression of leptin, RAS, TGF-β1, and proinflammatory cytokines. These changes may contribute to the development of lung fibrosis and AHR. VitD supplementation rescues these changes and may have therapeutic potential for asthma with obesity.

An Update of Medical Nutrition Therapy in Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a serious and frequent pregnancy complication that can lead to short and long-term risks for both mother and fetus. Different health organizations proposed different algorithms for the screening, diagnosis, and management of GDM. Medical Nutrition Therapy (MNT), together with physical exercise and frequent self-monitoring, represents the milestone for GDM treatment in order to reduce maternal and fetal complications. The pregnant woman should benefit from her family support and make changes in their lifestyles, changes that, in the end, will be beneficial for the whole family. The aim of this manuscript is to review the literature about the Medical Nutrition Therapy in GDM and its crucial role in GDM management.

The effects of vitamin D supplementation on glycemic control and maternal-neonatal outcomes in women with established gestational diabetes mellitus: A systematic review and meta-analysis

BACKGROUND & AIMS

Gestational Diabetes Mellitus (GDM) is associated with a well-documented range of adverse pregnancy outcomes. The present meta-analysis was conducted to evaluate the effects of vitamin D supplementation on glycemic control and maternal-neonatal outcomes in women with established GDM.

METHODS

Published literature was retrieved and screened from PubMed, Embase, Web of Science, CNKI (China National Knowledge Infrastructure), Wanfang, and Cochrane Center Register of Controlled Trails up to May 2020. RCTs of vitamin D supplementation on pregnant women with GDM were included.

RESULTS

19 RCTs (1550 participants) were eligible for meta-analyses. Overall, vitamin D supplementation significantly reduced serum fasting plasma glucose (FPG) (MD: -10.20 mg/dL, 95%CI: -13.43 to -6.96), insulin concentration (MD: -5.02 μIU/mL, 95%CI: -6.83 to -3.20) and the homeostasis model assessment of insulin resistance (HOMA-IR) (MD:-1.06, 95%CI: -1.40 to -0.72) in women with GDM. In addition, vitamin D supplementation in pregnant women with GDM significantly reduced adverse maternal outcomes including cesarean section (RR: 0.75, 95%CI: 0.63 to 0.89), maternal hospitalization (RR: 0.13, 95%CI: 0.02 to 0.98) and postpartum hemorrhage (RR: 0.47, 95%CI: 0.22 to 1.00). Several adverse neonatal complications including neonatal hyperbilirubinemia (RR: 0.47, 95%CI: 0.33 to 0.67), giant children (RR: 0.58, 95%CI: 0.38 to 0.89), polyhydramnios (RR: 0.42, 95% CI: 0.24 to 0.72), fetal distress (RR: 0.46, 95%CI: 0.24 to 0.90) and premature delivery (RR: 0.43, 95% CI: 0.26 to 0.72) were also significantly reduced.

CONCLUSIONS

This meta-analysis suggested that supplementation of GDM women with vitamin D may lead to an improvement in glycemic control and reduction of adverse maternal-neonatal outcomes.

Improving the endothelial dysfunction in type 2 diabetes with chromium and vitamin D3 byreducing homocysteine and oxidative stress: A randomized placebo-controlled trial

BACKGROUND

Chromium picolinate (CrPic) and vitamin D3 are known as two antioxidant micronutrients. Through inducing endothelial dysfunction, oxidants such as homocysteine (Hct) and malondialdehyde (MDA) lead to cardiovascular disease in type 2 diabetes mellitus (T2DM). No published data has directly examined the effects of these two antioxidants on improving the endothelial dysfunction in T2DM throughreducing homocysteine and oxidative stress.

METHODS

Subjects (n = 92) in this randomized, double blind, placebo-control study were randomly assigned to receive oral placebo (group I), D₃ (group II: 50,000 IU/ week), chromium picolinate (CrPic) (group III: 500 μg/day), and both vitamin D₃ and CrPic (group IV) for four months. Fasting blood samples were drawn at study baseline and following intervention to determine Hct, MDA, total antioxidant capacity (TAC), total thiol groups (SHs), vascular cell adhesion molecule- 1 (VCAM-1), and plasminogen activator inhibitor-1 (PAI-1).

RESULTS

After intervention, MDA significantly decreased in groups II and IV; TAC significantly increased in group IV, and SHs significantly augmented in group III; Hct was significantly reduced in groups II, III, and IV; and VCAM-1 significantly decreased in groups III and IV and PAI-1 was significantly reduced in groups II, III, and IV.

CONCLUSION

Our findings suggest that through reducing homocysteine and oxidative stress and improving endothelial dysfunction, chromium and vitamin D₃ co-supplementation might be predictive and preventive of cardiovascular diseasesassociated with T2DM. IRCT, IRCT20190610043852N1, registered 21 October 2019, https://fa.irct.ir/user/trial/42293/view.

The individual and joint effects of maternal 25(OH)D deficiency and gestational diabetes on infant birth size

BACKGROUND AND AIMS

To examine the independent effect of maternal serum 25-hydroxyvitamin D [25(OH)D] deficiency and its joint effect with gestational diabetes mellitus (GDM) on infant birth size.

METHODS AND RESULTS

This retrospective cohort study was conducted in 15,724 mother-offspring dyads in Beijing, China between 2016 and 2017. Outcomes included infant birth weight Z-score (adjusted for gestational age and sex) and large for gestational age (LGA). Exposures were maternal 25(OH)D concentrations. Linear and logistic regression models were used to assess the associations of exposures with continuous and binary outcomes, respectively. Exposure-outcome associations were not observed when analyzing 25(OH)D concentrations continuously or in quartiles (P > 0.05); however, mothers with severely deficient 25(OH)D concentrations (n = 307) had a decreased risk of LGA compared with those with sufficient 25(OH)D concentrations (≥30.0 ng/mL; n = 5400) (adjusted odds ratio (OR): 0.63; 95% confidence interval (CI): 0.42, 0.93). Compared to mothers with no 25(OH)D deficiency (≥20.0 ng/mL) and no GDM (n = 7975), those with both 25(OH)D deficiency and GDM (n = 1090) had 0.15 (95% CI: 0.09, 0.21) higher infant birth weight Z-score and a higher risk of LGA (OR: 1.29; 95% CI: 1.09, 1.52). Maternal 25(OH)D deficiency and GDM had additive interaction on the risk of LGA (relative risk due to interaction: 0.18).

CONCLUSION

Mothers with severely deficient 25(OH)D might have a decreased risk of LGA. However, the joint effect of maternal 25(OH)D deficiency and GDM might increase the risk of LGA. Our findings have clinical and public health implications and provide potential directions for future studies.

Prevention and Management of Gestational Diabetes Using Vitamin D Supplementation: An Overview and Appraisal of Clinical Trials

A number of studies have examined the role of vitamin D in reproductive processes and disorders of pregnancy such as gestational diabetes mellitus (GDM). Although observational studies have linked maternal vitamin D deficiency with a plethora of adverse pregnancy outcomes including GDM, intervention trials generally do not support the use of vitamin D supplementation for GDM prevention or management. This narrative review provides an up-to-date overview and critical appraisal of randomised controlled trials (RCTs) to describe the current state of knowledge regarding the efficacy of vitamin D supplementation for preventing and/or managing GDM. Overall, although RCT data indicates a potential benefit of vitamin D in maternal glycaemic control, results are highly disparate and the data published to date have not conclusively established the efficacy of vitamin D in GDM prevention. There are, however, several limitations within the existing literature, including some considerable challenges that are unique to vitamin D trials, which should be carefully considered in the interpretation of the evidence and design of future studies. For now, many unanswered questions remain, and there is still a need for adequately powered and well-designed trials before routine supplementation can be recommended in the context of GDM.

Evaluation of the efficacy of two doses of vitamin D supplementation on glycemic, lipidemic and oxidative stress biomarkers during pregnancy: a randomized clinical trial

BACKGROUND

Vitamin D deficiency during pregnancy is common and is likely to be associated with metabolic complications in the mother. The aim of this study was to assess the efficacy of two doses of vitamin D supplementation during pregnancy on maternal and cord blood vitamin D status and metabolic and oxidative stress biomarkers.

METHODS

The eligible pregnant women (n = 84) invited to participate in the study and randomly allocated to one of the two supplementation groups (1000 IU/d vitamin D and 2000 IU/d). Biochemical assessments of mothers including serum concentrations of 25(OH)D, calcium, phosphate, iPTH, fasting serum sugar (FBS), insulin, triglyceride, total cholesterol, LDL-C, HDL-C, malondialdehyde (MDA) and total antioxidant capacity (TAC) were done at the beginning and 34 weeks of gestation. Cord blood serum concentrations of 25(OH)D, iPTH, MDA and TAC were assessed at delivery as well. To determine the effects of vitamin D supplementation on metabolic markers 1-factor repeated-measures analysis of variance (ANOVA) was used. Between groups comparisons was done by using Independent-samples Student's t-test or Mann-Whitney test. P < 0.05 was considered as significant.

RESULTS

Supplementation with 1000 IU/d and 2000 IU/d vitamin D resulted in significant changes in vitamin D status over pregnancy (24.01 ± 21.7, P < 0.001 in 1000 IU/d group and 46.7 ± 30.6 nmol/L, P < 0.001 in 2000 IU/d group). Daily intake of 2000 compared with 1000 IU/d tended to increase the serum concentration of HDL-C (10 ± 8.37, P < 0.001 in 1000 IU/d group and 9.52 ± 11.39 mg/dL, P < 0.001 in 2000 IU/d group). A significant decrement in serum concentration of iPTH observed in both groups (- 4.18 ± 7.5, P = 0.002 in 1000 IU/d group and - 8.36 ± 14.17, P = 0.002 in 2000 IU/d group).

CONCLUSIONS

Supplementation with 2000 IU/d vitamin D as compared with 1000 IU/d, is more effective in promoting vitamin D status and HDL-C serum concentration and in decreasing iPTH over pregnancy.

TRIAL REGISTRATION

This trial is registered at clinicaltrials.gov ( NCT03308487 ). Registered 12 October 2017 'retrospectively registered'.

Diet and Healthy Lifestyle in the Management of Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) among pregnant women increases the risk of both short-term and long-term complications, such as birth complications, babies large for gestational age (LGA), and type 2 diabetes in both mother and offspring. Lifestyle changes are essential in the management of GDM. In this review, we seek to provide an overview of the lifestyle changes which can be recommended in the management of GDM. The diet recommended for women with GDM should contain sufficient macronutrients and micronutrients to support the growth of the foetus and, at the same time, limit postprandial glucose excursions and encourage appropriate maternal gestational weight gain. Blood glucose excursions and hyperglycaemic episodes depend on carbohydrate-intake. Therefore, nutritional counselling should focus on the type, amount, and distribution of carbohydrates in the diet. Further, physical activity has beneficial effects on glucose and insulin levels and it can contribute to a better glycaemic control.

The Molecular Mechanisms by Which Vitamin D Prevents Insulin Resistance and Associated Disorders

Numerous studies have shown that vitamin D deficiency is very common in modern societies and is perceived as an important risk factor in the development of insulin resistance and related diseases such as obesity and type 2 diabetes (T2DM). While it is generally accepted that vitamin D is a regulator of bone homeostasis, its ability to counteract insulin resistance is subject to debate. The goal of this communication is to review the molecular mechanism by which vitamin D reduces insulin resistance and related complications. The university library, PUBMED, and Google Scholar were searched to find relevant studies to be summarized in this review article. Insulin resistance is accompanied by chronic hyperglycaemia and inflammation. Recent studies have shown that vitamin D exhibits indirect antioxidative properties and participates in the maintenance of normal resting ROS level. Appealingly, vitamin D reduces inflammation and regulates Ca²⁺ level in many cell types. Therefore, the beneficial actions of vitamin D include diminished insulin resistance which is observed as an improvement of glucose and lipid metabolism in insulin-sensitive tissues.

Association Between Serum 25-OH-Vitamin D and Diabetic Foot Ulcer in Patients With Type 2 Diabetes

Background: Vitamin D deficiency has been associated with an increased risk in several diabetic complications. We aimed to evaluate the association between vitamin D and diabetic foot ulcer (DFU) in patients with type 2 diabetes. Methods: Fifty one patients were included in the study and divided into two groups for study of vitamin D, cholesterol, and triglycerides in blood serum on DFU. The association between vitamin D and DFU was measured by binary logistic regression analysis. The cut point of vitamin D for DFU was assessed by the receiver operating characteristic curve. Results: Levels of 25-OH-vitamin D were lower in patients with DFU than in DM group (P < 0.0001). The AUC of 25-OH-vitamin D was 0.8254 and had an optimal cut point value (13.68 ng/ml) for the identification of DFU, with a sensitivity of 90% and a specificity of 66.67% in all patients. Multivariate logistic regression analysis indicated that the significant risk factors included 25-OH-vitamin D level (P = 0.001, OR = 0.618) and HDL-C level (P = 0.038, OR = 0.012). Conclusion: Low serum 25-OH-vitamin D level was associated with DFU. This indication was more specific than cholesterol and triglycerides levels.

Iron Deficiency Anemia in Pregnancy: Novel Approaches for an Old Problem

Iron needs increase exponentially during pregnancy to meet the increased demands of the fetoplacental unit, to expand maternal erythrocyte mass, and to compensate for iron loss at delivery. In more than 80% of countries in the world, the prevalence of anemia in pregnancy is > 20% and could be considered a major public health problem. The global prevalence of anemia in pregnancy is estimated to be approximately 41.8%. Undiagnosed and untreated iron deficiency anemia (IDA) can have a great impact on maternal and fetal health. Indeed, chronic iron deficiency can affect the general wellbeing of the mother and leads to fatigue and reduced working capacity. Given the significant adverse impact on maternal-fetal outcomes, early recognition and treatment of this clinical condition is fundamental. Therefore, the laboratory assays are recommended from the first trimester to evaluate the iron status. Oral iron supplementation is the first line of treatment in cases of mild anemia. However, considering the numerous gastrointestinal side effects that often lead to poor compliance, other therapeutic strategies should be evaluated. This review aims to provide an overview of the current evidence about the management of IDA in pregnancy and available treatment options.

Clinical and Metabolic Responses to Magnesium Supplementation in Women with Polycystic Ovary Syndrome

We hypothesized that magnesium supplementation might help improve metabolic profiles and clinical symptoms of polycystic ovary syndrome (PCOS) through its role in insulin action. The present study aimed to investigate the effect of magnesium supplementation on metabolic profiles and levels of sex hormones in women with PCOS. In this parallel randomized, double-blind, placebo-controlled clinical trial, 60 women with PCOS aged 20-45 years were recruited. After stratification for body mass index (BMI), age, and types of medications, participants were randomly assigned to consume magnesium supplements (containing 250 mg magnesium oxide) or placebo for 8 weeks. To assess biochemical indicators, a venous blood sample was taken after an overnight fasting. The mean age of study participants was 26.4 years. We found that magnesium supplementation for 8 weeks among women with PCOS had favorable effects on BMI compared with the placebo group (changes from baseline in intervention group: - 0.31 ± 0.07 vs. 0.07 ± 0.09 kg/m² in control group). In addition, the supplementation lead to preventing the increase in waist circumference in intervention group compared with the control group (0.02 vs. 1.15 cm). No significant effects on glycemic variables and lipid profile were seen following the magnesium supplementation. A significant increase in serum LH levels in intervention group and a decrease in placebo group were observed (P = 0.01). Although we found a significant decrease in serum testosterone levels in intervention and placebo groups, comparing the changes between the two groups, a marginally significant difference in serum testosterone levels was found (51.65 vs. 47.80 in intervention, 43.41 vs. 39.46 in placebo, P = 0.08). A significant increase in serum dehydroepiandrogens (DHEA) (136.32 vs. 172.37 intervention, 102.74 vs. 120.15 placebo, P = 0.01) was seen in two groups. Magnesium supplementation had no significant effects on FSH, 17OH-progesteron, sex hormone-binding globulin (SHBG), and free androgen index (FAI) levels. We found evidence indicating that magnesium supplementation did not influence serum lipid profiles and glycemic indicators among women with PCOS. Magnesium supplementation resulted in reduced BMI and testosterone levels as well as increased DHEA concentrations in women with PCOS. Also, magnesium supplementation may increase serum LH levels. ClinicalTrials.gov IRCT registration no. NCT02178150.

Assessing the effect of MitoQ10 and Vitamin D3 on ovarian oxidative stress, steroidogenesis and histomorphology in DHEA induced PCOS mouse model

Polycystic ovary syndrome (PCOS) continues to be one of the most complex reproductive and endocrine disorder among women of reproductive age. Recent reports have identified close interaction of Vitamin D deficiency and oxidative stress (OS) in exacerbating the pathophysiology of PCOS. This current study aims at assessing the combine effect of MitoQ₁₀ and Vitamin D3 on dehydroepiandrosterone (DHEA) induced PCOS. Following successful induction of PCOS using DHEA, mice were organized into five groups (n = 8) namely: Negative Control (NC), Vitamin D3 Vehicle (VDV), Vitamin D3 (VD), MitoQ₁₀ (MQ), Vitamin D3 plus MitoQ₁₀ (V+M) and DHEA, ethanol and distilled water, Vitamin D3, MitoQ₁₀ and Vitamin D3 plus MitoQ₁₀ were respectively administered for 20 consecutive days. The study also included positive control (PC) group (n = 8) in which no treatment was applied. Treatment effects were assessed using hormonal assays, biochemical assays, Real-Time PCR, western blotting and histological analysis. Combination of Vitamin D3 and MitoQ₁₀ significantly reduced levels of estradiol, progesterone, FSH, LH, LH/FSH, SOD and MDA. The expression rate of mRNAs of 3β-HSD, Cyp19a1, Cyp11a1, StAR, Keap1, HO-1 and Nrf2 were also significantly low in V+M group. Moreover, the histomorphological inspection of ovaries from this group revealed many healthy follicles at various stages of development including few atretic follicles, pre-antral and antral follicles and many corpora lutea. The characteristics observed in this group were in many ways similar to that of the PC group. The combination of MitoQ₁₀ and Vitamin D3 may be potential candidate to ameliorate PCOS.

A systematic review and meta-analysis of the effect of Vitamin D-fortified food on glycemic indices

Some reports indicated that Vitamin D may improve glycaemia indices in diabetic patients. The aim of this systematic and meta-analysis was to evaluate effects of Vitamin D fortification on indices of glycemic control. Six databases (PubMed/Medline, ISI Web of Knowledge, Cochrane Library, Science Direct, Scopus, and Google Scholar) were searched, for randomized controlled trials that were published up to September 2018 and that compared the effect of Vitamin D-fortified food versus regular diet in relation to glycemic control. Of the 4,379 studies originally found, 11 articles remained to be assessed for meta-analysis. Vitamin D fortification was associated with a significant improvement in fasting serum glucose (mean difference [MD]: -2.772; 95% confidence interval [CI]: -5.435 to -0.109) and fasting serum insulin (MD: -2.937; 95% CI: -4.695 to -1.178) in patients with Type 2 diabetes mellitus. A diet with food enriched with Vitamin D was associated with a significant improvement in homeostatic model assessment of insulin resistance (MD: -1.608; 95% CI: -3.138 to -0.079) but was not associated with a significant reduction in hemoglobin A1C (MD: 0.034; 95% CI: -0.655 to 0.069). This meta-analysis indicates that Vitamin D fortification improves indices of glycemic control. Hence, food fortified with Vitamin D may be of potential therapeutic value in diabetic patients, as an adjuvant therapy.

A comparison of the risk of cesarean section in gestational diabetes mellitus patients supplemented antenatally with vitamin D containing supplements versus placebo: A systematic review and meta-analysis of double-blinded randomized controlled trials

The aim of this study was to study the role of vitamin D containing supplements in the risk of cesarean section (CS), a common complication in gestational diabetes mellitus (GDM) patients. An additional objective was to assess the risk of developing pre-eclampsia, preterm delivery, macrosomia, and polyhydramnios in these participants. Various electronic databases were searched for double-blinded parallel-arm randomized controlled trials that reported the incidence of CS in adult, non-insulin treated GDM patients who received vitamin D and placebo in different treatment arms, respectively. Next, each eligible trial’s risk of bias was assessed, and the effects of the above interventions on the respective outcomes were compared meta-analytically across the trials. This review included five Iranian trials sourcing data from nearly 380 participants. The risk of bias in the trials was primarily low. In contrast to the placebo group, the risk of CS [risk ratio (RR): 0.61, p=0.002, 95% confidence interval (CI): 0.44,0.83; I²=0%, p-value of Cochrane’s Q: 0.373) and macrosomia (RR: 0.31, p=0.006, 95% CI: 0.13,0.72; I²=0%, p-value of Cochrane’s Q: 0.935] was less in the vitamin D supplemented group. The remaining outcomes did not differ between the intervention groups. The antenatal use of vitamin D containing supplements in non-insulin treated GDM patients might reduce the risk of CS and macrosomia.

Daily versus stat vitamin D supplementation during pregnancy; A prospective cohort study

BACKGROUND

Despite favorable climatic conditions, vitamin D deficiency (VDD) is widespread in Pakistan. Current study was aimed to evaluate the prevalence of VDD in Pakistani pregnant women and effectiveness of various regimen of Vitamin D supplementation.

METHODOLOGY

This hospital-based prospective cohort study included pregnant women at 12th to 24th weeks of gestation attending Gynae clinic from October 2018 to April 2019. Patients were classified into control and treatment groups (Groups: G1, G2 and G3) according to the dose of vitamin D supplementation. Patients received various regimens of vitamin D including 2000 IU/day (G1), 5000 IU/day (G2) and stat 200000 IU (G3). The levels of vitamin D were measured before and after supplementation. The effectiveness of dosages were compared between and within the groups. Moreover, factors associated with vitamin D sufficiency and insufficiency were ascertained using appropriate statistical methods.

RESULTS

Among 281 pregnant women (mean age: 28.22 ± 4.61 years), VDD was prevalent in 47.3% cases. Vitamin D supplementation caused significant rise in the levels 25(OH)D in treatment groups, while there was no significant difference in control group. The highest mean increment in vitamin D (23.14 ± 11.18 ng/ml) was observed with dose 5000 IU/day followed by doses 200000 IU stat (21.06 ± 13.73 ng/ml) and 2000 IU/day (10.24 ± 5.65 ng/ml). Vitamin D toxicity was observed in one patient who received 200000 IU stat of vitamin D. The frequency of VDD following the supplementation was 5.7%. Education status, duration of sun exposure and use of sunblock was substantially associated with vitamin D sufficiency in the current study.

CONCLUSION

Our findings underscore the high proportion of VDD among pregnant women in Pakistan. Maternal vitamin D supplementation substantially improved the levels of 25(OH)D. Of three used regimens, the dose of 5000 IU/day is considered safe and equally effective as of 200000 IU stat. Since pregnancy is a time of tremendous growth and physiological changes for mother and her developing fetus with lifelong implications for the child, gestational vitamin D supplementation should be considered to ensure the optimal vitamin D accrual in pregnant women. This study generates the hypothesis that vitamin D supplementation at a dose of 5000 IU/day during pregnancy is superior to the other regimens. However, well-controlled randomized trials are needed to confirm these findings.

Combined Effect of Maternal Vitamin D Deficiency and Gestational Diabetes Mellitus on Trajectories of Ultrasound-Measured Fetal Growth: A Birth Cohort Study in Beijing, China

OBJECTIVE

Few studies have examined whether maternal 25(OH)D deficiency and gestational diabetes mellitus (GDM) jointly affect fetal growth. We aimed to examine the separate and combined effects of maternal 25(OH)D deficiency and GDM on trajectories of fetal growth.

METHODS

We established a birth cohort (2016-2017) with 10,913 singleton pregnancies in Tongzhou Maternal and Child Health Hospital of Beijing, China. Maternal 25(OH)D deficiency (serum 25(OH)D concentration < 20.0 ng/mL) was detected, and GDM was diagnosed at 24~28 gestational weeks. Fetal growth was assessed by longitudinal ultrasound measurements of estimated fetal weight (EFW) and abdominal circumference (AC) from 28 gestational weeks to delivery, both of which were standardized as gestational-age-adjusted Z-score. A k-means algorithm was used to cluster the longitudinal measurements (trajectories) of fetal growth. Logistic regression models were used for estimating exposure-outcome associations and additive interactions.

RESULTS

We identified two distinct trajectories of fetal growth, and the faster one resembling the 90^th centile curve in the reference population was classified as excessive fetal growth. Maternal 25(OH)D deficiency and GDM were independently associated with an increased risk of excessive fetal growth. The combination of maternal 25(OH)D deficiency and GDM was associated with an increased risk of excessive fetal growth assessed by EFW Z-score (odds ratio (OR): 1.36; 95% confidence interval (CI): 1.15~1.62) and AC Z-score (OR (95% CI): 1.32 (1.11~1.56)), but the relative excess risks attributable to interaction were nonsignificant (P > 0.05).

CONCLUSION

Maternal 25(OH)D deficiency and GDM may jointly increase the risk of excessive fetal growth. Interventions for pregnancies with GDM may be more beneficial for those with 25(OH)D deficiency than those without regarding risk of excessive fetal growth, if confirmed in a large sample.